1. Field of the Invention
The present invention relates to a power supply circuit and electronic equipment.
2. Description of the Related Art
In power supply circuits, such as a switching regulator, that generates an output voltage of a target level from an input voltage, there is a possibility that due to a short-circuit in a circuit, etc., an output current for a load supplied with the output voltage rises to an excessive level. When a state where the output current thus rises, i.e., an overcurrent state, continues, components making up the power supply circuit and a load may be in danger of being destroyed. Many of the power supply circuits include an overcurrent protection function that an overcurrent state is cancelled by stopping an operation of generating the output voltage when the overcurrent is detected (Japanese Patent Application Laid-open Publication No. 2007-6651, for example).
When the load is driven by using the output voltage generated by the power supply circuit, a state where the output current becomes temporarily large when activating the load, i.e., an inrush current, sometimes occurs. For example, in a case of driving a hard disk drive, the inrush current occurs when activating a motor for rotating the hard disk.
In a case of the power supply circuit including the overcurrent protection function, the operation of generating the output voltage is stopped while the inrush current exceeds an overcurrent detection level. Therefore, in a period during which the operation of generating the output voltage is stopped due to the inrush current, the level of the output voltage is decreased from the target level, and thus, there is a case that the load cannot normally be driven.